Cernunnos
by castielssock
Summary: They'd been in purgatory less than five weeks when it happened. Written for a prompt on the kink meme- contains non-con, knotting, forced breeding, feminization, slight D/s, and references to mpreg. Full warnings/summary inside. Disclaimer- I don't own this and I'm sure as hell not making any profit from it. Reviews would be awesome!


**Written for a prompt on the kink meme: **Someone in Purgatory decides they want to breed themselves a nephilim.**  
Warnings/Kinks: **Non-con, knotting, heat, slight feminization, body modification, transformation, voyeurism, bondage, allusions to mpreg, D/s undertones. Not beta'd.

...

They'd been in purgatory less than five weeks when it happened.

It was, ironically, a cave they were hauled up in; one a very few places they'd thought had the teeniest amount of safety left in them, because for a place that was mostly forest, purgatory sure as hell didn't have much in the way of shelter.

They'd noticed after the first day that there were buildings dotted around, houses, but after the second day when they'd decided to throw caution to the flames—because what were the chances of them surviving out here in the open—and had approached a little shack to check it out, they realised their first real truth of purgatory; nothing was as it seemed.

Certainly least of all the buildings, fucking traps lurking in paper-card walls that they were, snapping with teeth and claws the second you entered like a goddamn spider in a web, waiting to sneak out and grab and finish off in scant seconds. Dean had learned quickly that he couldn't trust his eyes here.

The only thing he did trust, was Castiel.

It had surprised him, when he'd realised it, when he'd stopped and thought about it and something had just _clicked _and he could suddenly say 'yeah, I trust him' again.

He hadn't forgiven Castiel for what he'd done, for what he'd put Dean, _Sam _through, but being stuck in a world of monsters you'd never even heard of, alongside the familiar ones that had long since made themselves home under your bed, and having every one of them out for your blood kind of hurried things along.

Purgatory, for all its hostility and raw lethality, was surprisingly good therapy when the only choices you had were to either work through your issues, or die.

Honestly, when Dean had a spare few minutes to sit and breathe and dabble in introspection in a way he avoided entirely on Earth, but had nothing left to distract him from it here, he could admit to himself that it was a relief.

Not trusting Cas, even in his fucked-up, half crazy, barely recognisable state was difficult, left him feeling strained and unnatural, like holding your breath under water.

He supposed when you spent so long piling your faith into a single being, you were bound to feel lost when it was torn from you like razor talons dragging you by the umbilical cord from your mother's womb.

But after that point, his thoughts got too messy, too hard to tell apart from emotions, and there wasn't room for that kind of weakness down here.

He had to think lineally, in lines and connected dots, in rationality because that was the only thing Dean had to cling onto in the ghost-train wonderland tumbling around him.

If he let go of reality for one moment and delved too far into the realms of thought and fancy, Dean was afraid he wouldn't find his way back again. And he had to get back.

Back to Sammy.

They'd worked out a system early on, when it became pretty obvious that Castiel needed rest here as well, needed almost as much sleep as Dean did. He still had his powers, for the most part, but they were depleted, reduced.

He'd once described it like locking your keys inside your car, all the journeys you could ever possibly hope to take at your feet and only the thinnest barrier separating you from them, but a barrier thick enough to hold you back, to keep you at bay.

Dean hadn't quite known what to make of that, hadn't known if Castiel was speaking in those nonsense tongues of his again, so he'd just nodded his head and pretended he knew. Cas didn't need doubts, contradiction.

He seemed so happy when Dean played along.

Castiel had kept watch while he slept, and vise versa, and their days were a constant loop of sleeping, waking, watching, and moving on as quietly and quickly as possible to avoid detection, covering their tracks as well as they could manage and never looking back.

Looking back meant seeing the things that were maybe tracking you, maybe just another hallucination, but Dean had come to understand that as long as you didn't look back, they wouldn't move forward. And that seemed a fair enough trade.

They weren't without conflict though, not by far. They killed their way through enough fanged bastards to survive, but didn't kill too many, and when they did it was discreetly, enough so that it wouldn't get them noticed. They couldn't afford to be the resident hunter and his pet angel here.

It was already bad enough that the things that loomed out in all that blackness could smell the human on him—whatever else Castiel's fragile grace was protecting was best left undiscovered.

They'd had no idea where they were going though, no fucking clue on how to get out of there despite the way Dean liked to pitch weary, doomed ideas and Castiel would rattle on in dreamy ideals and fairy tales.

This was purgatory and the thick, grey fog so tangible it pulsed_,_ _breathed_ around them, didn't only cloud your vision, it took your mind down too. A lot of energy was spent on simply trying to guide through the haze and, when they finally did so, on using that left over brain power to make it through to the next day. There was rarely much left over strategizing.

It didn't help that everything they knew from before, everything they'd spent their whole lives rearing and being trained for fell apart worthless and laughable in their fingers because they were in a monster's world now, and _they _were the hunted.

Their rules couldn't work here. They had to adapt.

Dean remembered sometimes what Meg had said, all that crap about finding a cause and sticking to it.

Sometimes he'd catch Castiel staring at him, his eyes wide and so jagged with trust you could cut yourself on it, like the way a dog looks at its master, but those times he'd shiver and look away.

He tried not to think about what cause Castiel had found this time around; the last already having left them in ribbons. Dean only had room to serve his own, and that centred on them getting the hell out of here, as soon as they could.

Things never worked out like that though, did they?

He couldn't even remember what they'd been doing exactly before it happened, the days having bled into a incomprehensible blur weeks ago, but he had a fuzzy recollection of scuffing dirt with his shoe and Cas talking animatedly at the side of him about the history of broccoli cultivation in ancient Italy.

He didn't know if they'd just gotten sloppy or if they'd paused for a moment too long, or if the living-shadows here were just that good that they could outsmart a hunter that helped take down Lucifer and an Angel that once held the keys to the universe in his fingers.

But then, Dean supposed when you were trapped in this deranged, sadistic arena with nothing to do to pass the time but slaughter and maim, you learned a few tricks.

Honestly, all he knew for sure though was that there had been a crack, like a whip slicing through air, and then Castiel had been shouting his name and Dean was scrambling to his feet, hand going for the gun that was all too useless here anyway.

But it didn't matter what he'd have done, how hard he'd have fought—by the time he was standing upright, the world was already going dark and he'd been too slow.

The only fucking time in a long time he'd been _too slow_ and he'd ended up killing them.

The last thought Dean had before unconsciousness set in had felt like an apology, but to who or what for, he wasn't quite sure.

In the end, though, it had turned out they weren't dead, or at least no more so than any other discarded soul left here, because Dean had been dead, and death, _Hell, _had nothing on this.

...

When he came to, the first thing Dean noticed was the stench. It was putrid with death and rot, much like the rest of purgatory, the cesspit that it was, something you might have called God-forsaken if you didn't already live in a universe that God had long since fled.

Only here, though, the foul, fetid odour had mingled with something acidic, something almost chemical—kind of like sulfur, but Dean knew that stuff all to well to know that it wasn't anything close.

He gagged with it, though, whatever it was, his eyes watering with the retches of his throat as he tried to breathe through them, to get a hold of himself, which was easier said then done.

His head throbbed and ached like he'd gone ten rounds with a wendigo, but if there was any other sensation in his body right then, he couldn't feel it through terrifying numbness.

Once the world around him finally slowed its dance, Dean could see far enough into the darkness to realise that he was still in a cave, but when his eyes focused well enough, nearby crackles and glimmers of bright orange flames became clear, his retinas stinging with the brightness.

It was damn rare that he or Cas dared to risk lighting up a fire, the glow of them far too attractive in the dense, perpetual blackness, and Dean's heart sank with the knowledge, with the weight of reality.

This wasn't their cave. They weren't alone.

He tried to move, but his arms were weak and his head clouded, hands and feet bound to the wall behind him with what felt like scratchy, simple hemp.

It was the coldness of the unyielding, stone wall against his back that alerted him to his lack of clothes, and looking down pretty much solidified that theory. Yeah. Not good.

His ears were ringing high-pitched and constant, but he could make out a slight murmur somewhere in the distance, and his eyes sought out the source as they'd been trained to, but if Dean had the foresight, he'd have told himself to shut them tight and denying, to block out the shit he was about to see, as if closing your eyes and counting to ten made the bad things go away. As if it ever had.

The cave curved off towards a rounded centre, like the eye of the fucking storm, and circled around it was a group of some kind of monster he had no name for, couldn't place, and that was the norm here, wasn't it? To not know what the hell was going on, what the hell they were dealing with?

All he knew was that they were tall and human-looking, if not for the thick, greyish scales covering their bodies, but he didn't have time to speculate, because then he saw what they were gathered around and something in him _shattered. _

In the middle of this circle jerk of freaks was Castiel, bound, much like Dean, only face down, cuffed to some kind of table or bench and unmoving. Dean blinked a few times, some vital kind of processor shutting down and crapping out for a minute, like it expected time to slow down and wait for it, but time did no such thing and the creatures continued to move, continued to lord over Castiel and, fuck, was that _chanting? _

If it was, it was a language Dean was sure he'd never heard. He wouldn't have been surprised if it had never even been uttered on Earth, but it was _old, _and he could tell that much.

As soon as his brain jump started again, Dean was struggling in his bonds, eyes scanning around him for a vulnerability in the structure, for a loose knot, for _anything, _just to get him out of here, because whatever that was, it was some pretty high grade hoodoo. It had to be, to keep an angel (fallen as he was) bound and unconscious like that, and Dean didn't feel like waiting around for when they served him up as the main course. He had to get free, get Cas, and get _out of here. _

He felt wild, his heart beating so hard and fast in his chest, he was sure they'd hear it, sure they'd whirl around and spot him any moment but they didn't. They just kept... kept _carving_.

Dean squinted and he could see what they were doing now, around the shadows of their forms, the way metal glinted dangerously in the fire light, the way it came down like a caress over Castiel's skin, broke open his flesh and chased the blood that spilled out like tears.

It took a moment to register, but Dean traced the path of the marks back over naked Castiel's body, saw where they'd been littered across his back, on his wrists, even carved into the ropes and cuffs keeping him pinned- _sigils. _

Dean was yelling out before he knew it.

"_Hey_, you sons of bitches! Get the hell away from him."

It unnerved Dean how effortlessly they ignored him, the way they carried on without even shifting out of their rhythm, without pausing in notice of his existence. They just worked, calm and focused, like they had all the time in the world, even as Dean yanked and pulled at his bonds, even as he fought to free himself, even when he got fucking _nowhere _for his efforts. _They _had _all the time in the world._

Eventually, and Dean couldn't really tell how much time had passed, could only stare in fear and rage as they carried on doing... whatever the fuck it was they were doing to Cas, one of them turned to him, its scaled, mangled face twisted into a smile that may have been human once, but was pure bestial now.

Dean fought his shiver down, he'd seen worse, he'd _been _worse, but his pulse thrummed with barely-concealed terror. It wasn't the creature that scared him, so much as the fact that it was damn likely that he'd failed the only mission they had down here. To live. To get back home. To not fucking _die _here.

He couldn't stand to look at Cas then, but the creature didn't seem to want him to, just found his gaze and held it with too-warm, too-green eyes that seemed to know everything about him. Dean was reminded of Alastair.

"Ah, our second little saviour has woken. Good of you to join us."

The thing's voice seemed almost disjointed from its mouth, too crisp and mechanical like it had only just downloaded English into whatever organ it had that passed for a brain, but it was its tone that had Dean's stomach twisting sourly. The softness of it that was too rotten around the edges pull off a convincing effort at gentleness, and Dean didn't know if it should have been possible to speak in a decayed cadence, but this thing managed it.

Dean had learned years ago how to save face though, to _never let your enemies know they've got you beat, Dean, don't you ever let them know they're getting to you; that's how you die_. Instead, he curled his lips as his body squared off to look as menacing as it could from within the cradle of ropes holding it still, which apparently, going by the creature's expression, was not very menacing at all.

"You let him go, you goddamn freaks," Dean spat at the creature's face, because getting Castiel out of here was top priority, their best shot at survival, "You wanna play finger paint on someone, why don't you try it out the guy who's conscious?"

The demon-thing snorted, like Dean was some endearing fucking pet that had performed a neat trick, like he was five seconds away from fondly patting his head and Dean didn't know whether to be angry or terrified. He settled for seriously fucking pissed.

"Actually, we're almost done with you," it chuckled, freaking _chuckled, _"Though you are right, we really should press on."

Dean scarcely had time to feel the ice thrills shooting down his spine before a second, a third monster was stepping close to him, several pots and containers in their hands, completely unfazed by his squirming and shouting as he tried to kick out, tried to protect himself, to escape.

Clawed fingers wrapped around his arms and hips, kept him still, all unnatural, uncompromising strength holding him exactly where it had put him, like he was a chess piece, and Dean felt fury, hatred barrel through him, almost crippling him in its potency, screaming at him to stabshootburn, to _win. _

But if it wasn't for the ropes, for the hands keeping him upright, Dean didn't even think he'd be standing, and the despair of it swelled in his chest, reminded him of the nightmare times that were memories and the days he spent promising himself that it would _never _happen again.

He didn't give up fighting, of course he didn't, but they didn't stop what they were doing either, just slicked him up in this sludgy substance—some kind of paint maybe. He hissed in pain as they slid it in complex patterns over his skin, over the wounds they'd apparently already carved out of him, and he swore and he thrashed and he cursed, calling out for Cas, for Sam, for a God that had never listened, but he may as well have gone placid and complacent for all good it did him.

The two other creatures moved to put their things down and for a second, Dean almost believed that was the end of it, but of course it wasn't.

They were back again in an instant, grabbing his face and pushing a foul tasting mixture down his throat, and Dean could feel it tear through him like a buzzsaw taken to flesh, splitting his insides in two with livid acidity, relentless brutality.

He seized up, garbled screams leaving his mouth at the intensity. It was like being torn apart and dismantled and then reassembled again with every passing second, something at the core of him twisting and rebuilding with every beat, and Dean knew what this was—he'd wielded Alastair's knife for ten years, he knew torture.

He'd learned there was a beautiful kind of torture in recreating another's shape around them, stripping of their last comfort—the safety and familiarity of their own form—and then using it again them. It never failed to get them to break.

As his body contorted and rearranged itself from the inside out, Dean howled and spat and grit his teeth, but he knew, he _knew_, that was what they were doing here. He just didn't have the resources to wonder about the whys and what-fors.

It took a while for his struggling to lessen, the core of him rippling with red-hot agony, as the substance passed through him like lava and Dean could feel every last excruciating inch, jolting and jerking helplessly where he was suspended.

It was Hell, and much worse, and eventually he found himself crumpling; exhausted and existing only to feel the pain engulfing him, with unhidden moans and hisses. The creatures hadn't seemed to have moved throughout the entire ordeal.

They barely paid him any notice, as though the idea of him escaping hadn't occurred to them, but it didn't seem to be because they lacked the intelligence to plan for it, or because they were too caught up with what they were doing (and what the fuck _was_ that anyway?). It was more like they seemed not to even think it could be a possibility, that it was ridiculous to even consider the concept, so they didn't bother trying. They already knew the outcome.

That thought, for some reason, unsettled Dean more than anything else. The thought that he was completely, utterly powerless.

Distantly, he registered them detaching him from the wall after a few minutes, and any other time that would have been his cue to strike out, to fight, to run, but his body still reeled from the pain, and swam from the hazy narcotics fogging his system. Dean could barely even _think_ about running, and his mind grew a little more distant with every moment. If they'd drugged him, they'd done a hell of a job of it.

He did notice, however, when they dragged him over to Castiel's bowed form, forcing Dean with insistent hands into place behind him, and up close Dean could tell now it was definitely a bench Castiel was crumpled over. More importantly, he could see that Castiel was _awake, _awake and mumbling out sobbed nonsense into the leather beneath him, as though whatever fragile sanity he'd managed to cultivate had been ripped away from under his feet, leaving him shrivelled and vulnerable and horribly undone.

"Fuck, let him go!" Dean coughed again, his voice coming out a pull of glass and gravel, but it was useless. They weren't listening, and it _hurt_, and no-one was coming for him. It was just the two of them, just him and Cas, and God, this was it.

"It's gonna be okay, Cas, we're gonna get out of here," Dean slurred, drooped in the demon's hold, muscles twitching where they wanted to break free, but he hardly even recognised the words that poured from his own lips. So how was he supposed to expect Castiel, so far gone as the guy seemed, to understand them too?

But still, he had to try, had to say something, because they couldn't just go out alone, unspoken. Not after everything they'd been through.

"Hang in there, buddy, y'hear?"

But Castiel didn't hear, or at least gave no indication that he did, only whined like a pained animal, looking more fragile and small than Dean had ever seen him and it was frightening, goddammit, it was _wrong_.

He remembered the Angel that had hauled his ass up from Hell and then backed him into a corner and demanded his respect with the threat of throwing him back in if he didn't give it. Dean wondered what had ever happened to him.

Castiel was still babbling half-words and crazed sounds to himself, his fists clenching and unclenching, and whenever he opened his eyes, they were wild, white things; desperate and scared, like a wounded wolf.

Fear lurched inside of Dean, even through the fog dragging his body down, and he looked around, almost frenzied in his need to escape, to help Cas, to do _something_. Jesus Christ, what did these things even _want_?

The creature that had spoken to him before—Dean figured it to be the leader—laughed behind him, this low, throaty sound that made Dean want to gag with nausea and he just wished the world would stop _spinning_ for a second.

"He can't understand you right now," the thing was saying, and it took Dean a moment to realise it was talking about Castiel. "He can't understand anything that's not buried deep inside him, filling up all that nasty emptiness"

The words didn't make any sense, but he could tell they were derisive, cruel, and they made Dean want to spit in its face all the same. Before he could find the opportunity or the will, though, it started speaking again.

"He's in heat," it said plainly, dragging the curve of its filthy, long claws over Castiel's bare back, smirking as the body under its fingers jolted and keened like it was pure torture to even be touched. Or to not be.

"Perfect for it really. All that grace wrapped up in a pretty, malleable little vessel, just made for someone to come along, stick their hands in and recreate. Own."

It laughed, and Dean wanted it dead, wanted to tear its tongue from its mouth, just to get it to shut up talking about Cas like it knew anything about him, like it could ever hope to understand him when Dean on his best days only had the barest of glimpses.

"Pathetic bastard. Probably doesn't feel even complete without something lording over him."

It had made its way to Castiel's front now, and Dean hated the way it looked down at his friend (and he still had that title, he _did_), as though he was something pitiful. Dean wondered then if that was how _he_ looked at Cas as well, and he hated that idea even more.

"Really," it murmured absently, "we're doing him a favour."

"What did you do to him?" Dean demanded, rough and sloppy, the gasped-out threat he meant to push behind his words lost somewhere in the drunken tone of them.

The creature's words meant nothing to Dean yet, may as well have been Enochian, and if they were going to die here, he wanted to know what the fuck it was that would kill them.

But there was no answer, just hands coming from nowhere and shoving him suddenly down, so quick and unwavering the air in his lungs seized up for a moment, like gravity stopped being a thing.

They were pushing Dean's face against Castiel's neck then, and his eyes went wide, arms fighting back on reflex and he wasn't even trying to figure how what they were doing anymore, he just needed it to _stop_, but they pressed and pressed and he didn't know not to inhale.

By the time he figured out he shouldn't, once again, it was too late.

He felt it crash through him; something thick and insistent, and completely unrelenting. Like an instant-high, like some special mix of narcotics guaranteed to sky-rocket you up into self destruction and not let you down again until you were addicted and craving another hit.

Dean _breathed_, deep and hungry, filled his lungs with it like it was impossible to resist and his back arched as he lurched backwards and jolted forwards all at once, half of his mind clawing to get closer, the other half scrambling to get away.

But goddammit that _scent;_ sweet and intoxicating and so thick with promise that Dean swore he could feel it rubbing up against him, could feel it taking him over, could feel resistance flee.

"I told you," the creature, the _demon_, finally replied, all sense collapsing with its words.

"He's in heat."

Dean was breaking apart. His blood was hot, _broiling_ underneath skin that suddenly felt too waxen, too close.

He needed to peel it off, layer by layer, to tear at it if he had to, but he couldn't move, could only endure as wave after wave of this... _scent_ slammed into him, clutching and slashing at his flesh, demanding and greedy, refusing to be ignored.

Dean's spine tingled and prickled with something eager enough to feel like adrenaline but more than aggressive enough for him to think of testosterone, but all of it gone into overdrive, gone nuclear. He couldn't concentrate, couldn't hear or think, even as the small part of him that was still himself screamed itself raw trying to hold onto reality.

Even that part was fading though, quickly eroding under the building tattoo in his head, a constant rhythm that provided a backtrack to the flayed, static, foreign thoughts in his mind, and the further he was dragged down into it, the louder, clearer those words became. _Heatheatmineclaim._

"That's it, little breeder," the creature was saying, its voice a soft murmur, everywhere at once, sticking to his skin and confusing his nerves.

"You're feeling it now, aren't you?"

It was Dean's turn not to answer now, but he _couldn't_. The blood in his body surged, entangled itself with the haze of his mind and overwhelmed him, took him hostage. It pumped and pulsed and drowned him, circling him like prey while his body quaked under the force of it, filling out downwards in ways he never expected or wanted and _what was happening to him_?

"You're going to help us leave this prison. The two of you." It smiled. "What luck, to find such pretty little saviours."

Dean thought that maybe it was saying more then, maybe telling him what this was, what they were doing, but its words were deranged anyway and Dean just... _didn't fucking care anymore_.

He didn't want to hear the words, just wanted... wanted _something_, and it was like a concealed itch, he couldn't quite reach, couldn't scratch, and it was driving him crazy.

He knew he wanted to take that something, to possess it so much it panged like starvation inside of him, but he had no fucking idea what the 'something' was, or how he could get it.

The terrible thing was, he didn't have to wonder. The creatures were there, all around him, breathing and shifting like flesh walls keeping him locked inside this room, and then they were leading him forward, guiding hands pressing him against Castiel's exposed backside.

But Castiel had them beat, the delirious angel moaning at the contact, instantly, _mindlessly_, rolling his ass back against Dean's groin and that was fucking _it_.

Dean tore forward, so sudden and furious, a force so entirely unnatural that it would have frightened him at any other time, but so strong that the ropes snapped free of whatever was holding them taut and Dean's hands could move again. The things surrounding them made no move to re-restrain him, but Dean had stopped thinking about them entirely.

Right now, he could only think about _claiming_

He growled, so vicious and primal he'd have never have recognised the sound as having come from himself if he'd had the presence of mind to consider it, but he didn't.

Instead, he grabbed Castiel's shivering, mewling form by the hips and dragged him down, brutal and splitting onto Dean's cock like it was all he could ever possibly think to do, watching how Castiel snapped back and _screamed _with it.

In that moment, it was as though there had been no other reason for his entire existence than to go through all the necessary paths and trials that had brought him here, that had taken him to this instance where he was buried balls deep in Cas, and burning with an absurd, irrational joy like he'd found home again, and it was fucking _maddening_.

Dean groaned out, a whine of ruined appreciation on his lips, and an awed, surprised part of him registered _wet, _while an even smaller part of him wanted to scream and puke and fight, but it was all drowned out by the part of him that cried with a gratified _yes. _

"Feels good, doesn't it?" the bastard that put them here was saying, but Dean's mind was just a scrambled mess of agreement, strings of _yesyesyes_ linked together aimlessly, because it _did_.

Castiel was so hot, so tight and perfect, so fucking _wet_ around him and Dean thought he could die from just the feeling of it, thought he could die if he didn't get more.

"It's okay, Dean, let yourself go," the demon encouraging, sounding positively fucking gleeful, "Let yourself breed your bitch like you want to. You can have him"

Dean trembled, and his hips drove forward, pulled back for barely a second before he was fucking furiously back into Castiel's ass again, hearing the angel howl out under him, but warming Cas up, giving him adjustment time was just not an option. He couldn't breathe, couldn't pause, could only keep going, thrusting deep and constant, without logic or thought or sense. Just pure _need_.

His throat and chest tightened with the urge for air, animal grunts and sounds leaving his lax mouth, and he was breaking open fast. His nails scraped rough and ragged over Castiel's back, raw little lines following them, but Castiel just _took _it, just moaned and pushed back against him, muscles tightening and Dean felt himself give in to the truth of the creature's words, felt that primitive part of him snarl with excitement and satisfaction, because yes. This was his bitch, his mate, _hishishis_.

He wasn't the only one that seemed satisfied with that, either.

"I knew you were the ones. You're going to make us lots of little Nephilim," the leader explained, circling them with appraising eyes and a smile in the informative words Dean couldn't care less about right then.

"Breed an army for us. It only took our old Leviathan friends one helpful little angel to crack their way through to Earth. Imagine what we could do with a few dozen?"

That stuttered something in Dean, stabbed deep enough through the haze that it pummeled into him like a dangerous, fatal blow to his head, brought some amount of awareness with it.

He didn't know if it was the mention of the Leviathan, or if it was how things were starting to click into place, but Dean reeled back, a little, even as his hips continued to pound forward, to fuck into Castiel's body; he couldn't ignore this.

"Tell me, angel, did the Nephilim really grow to be giants?" it asked Castiel, but only received a moan and an angry twitch of hips at Dean's slightly slowed rhythm in response, and the demon laughed again, curling its fingers over Castiel's hair, a mocking kind of affection spread out over its face.

Dean wanted to cram it full of salt rounds.

"You s-son of a bitch," he panted, but it was a weak rebellion and he was elevated back onto those puppet strings as soon as it had left his mouth, the thick fog beating him back down again, sinking its teeth in with vengeance now, and Dean practically roared, knees buckling under the weight of it.

The creature may have been laughing, crowing out in victory, but Dean couldn't hear. Couldn't register anything beyond the booming of his own blood.

All he wanted again was more, faster, closer, tighter, to bury himself deeper and rut into the exposed open body under him until it was bursting with cock and come and whatever else Dean wanted to put inside of it, because the body underneath him was _his _and he'd mark it up from the inside out just to prove it.

Castiel's arms flexed in their bondage, his head lolling backwards and exposing his neck and Dean growled his approval at the clear sign of submission, his teeth latching on and biting down hard, possessiveness scorching like a brand in his gut. He couldn't wait to see the pretty, purple blotches he'd leave behind scattered out over all that pale skin. Castiel would look so good in his ownership.

"That's it, there's a good girl," it was practically crooning now, rubbing Castiel's scalp in caresses that were too degrading to be gentle.

"Is she tightening her pussy for you? I bet she is, bet that slutty little hole is just desperate to milk all that come right out of you."

Dean moaned, couldn't help it, because it seemed that his ears worked as long as they were picking up filthy words, and fuck, but Cas _was_ tightening around him, was twitching and clenching like Dean's cock was the best thing in the world, clamping down and taking it like a professional whore, and he was just so fucking _good_, Dean could have wept.

"Poor little angel can't even help it," the demon carried on, probably talking to itself at this point, sounding almost curious, "Look how badly her body wants it. Wants to be bred so full and swollen, just like a good little bitch."

The words were boiling, searing, but they were only ammunition enough to bring about a fresh wave of desire rolling through Dean like something tangible, and he snarled with it, nothing human in the noise at all.

It occurred to him later that the creature's tone wasn't even dirty, wasn't meant to arouse. It was mocking and amused, and maybe just a little fascinated, but Dean knew it couldn't give a flying fuck about his pleasure or even its own, just wanted to document and humiliate.

That might have seemed fruitless for all Dean cared about it right then, for all that Cas could ever care about those words; about obscenities meant to sting and inflict damage, but later when he remembered again, when things came rushing back to him, the shame was like vertigo and no amount of Winchester bravado was quite enough to mask it.

But that was probably the creature's design the whole time. It seemed to enjoy Dean's torment when he was sober enough to process it even more so than when he was lust-drunk.

They were Lilu demons—these creatures—Dean would come to learn later, when Cas had regained enough of reality to inform him so, ancient predecessors to the incubi. According to Castiel, this whole thing matched their M.O near perfectly. The Lilu loved to inflict humiliation, loved breaking their victims, and most importantly, loved to focus on child-rearing. If Dean had known that at the time though, he still wasn't sure he'd have been able to stop.

"You want it too, don't you?" it carried on, relentless, "Want to watch this pretty little angel whore split herself wide and open, getting all knocked up on your cock like a good slut should, getting nice and pregnant and round for us."

He did, he _did_, God help him, even if his mind didn't understand what they meant, the words pierced right into him, injected him with bruised endorphins and greedy chemicals and his body pulsed with rightness, told him that this was exactly what they were meant for, that Castiel was made to bend over for him, to stay put while Dean bred him full with his child.

It wasn't possible, it _shouldn't_ have been possible, but Dean didn't care about that right then, didn't give a fuck about their biology or their condition or whatever the fuck else, he was going to fuck Castiel so good it left him open and wet and fucking pregnant in the end.

That irrational, animal part of Dean couldn't wait to see Cas like that; belly all big and rounded, sore little tits swollen and leaking milk for all the babies Dean had fucked into him. His cock throbbed, fucking _hurt _with want for it, hips pounding into the tight, dripping hole, and Dean could feel it clench down around him like it wanted everything that was being offered, like Castiel knew he was a bitch and craved everything that came with it, was _hungry _to be bred.

"That's it, Dean-o, keep it up." the demon praised him, and something quiet and small in Dean wished it had the strength left to tell it to go to Hell.

"Breed her cunt up. It'll be good practice. You're going to be spending a lot of time in that pussy, keeping it stuffed full and pregnant. Won't that be nice?"

The rest of Dean, though, the parts that weren't his own (or at least that's what he forced himself to believe later, because anything else would be too heartbreaking, too shattering to accept) roared with delight at the idea, at the promise of more of this, more of Castiel, and he could feel it everywhere in his body, spreading without compromise.

The hairs on his skin stood up in thrills, the blood—where it wasn't pooled at his groin—rushed through him like pinpricks and his nerves sizzled with desire, the concoction in his mind running a little hotter.

He wanted, he _wanted_ so much he couldn't stand it, couldn't breathe. His chest hurt from trying to drag in breaths that were second-priority to everything else, and his muscles burned from the exertion of the constant, ruthless fucking, but he just couldn't stop.

Dean wasn't holding anything back now, couldn't dream to, his thrusts urgent and frenzied, hips snapping forward on auto-pilot, fingers gripping tight, nails digging in until they clawed down and tore at skin in Dean's impatience to pull Castiel back onto his cock quicker, harder, to fucking _ruin_ him.

"D-Dean."

It was distant and quiet, muffled by the leather that Castiel's mouth was pressed against, but Dean could just about make it out, could hear the quiver in Castiel's voice, the plea and the fear that told him Castiel was just enough himself for this to matter.

Those little parts of Dean reared up and became a little more solid, raced to fling themselves to the forefront of his mind, if only for a few seconds, if only to reach Castiel, to comfort with anything he could spare.

"God, f-fuck, Cas-" Dean gasped, his head pounding with the effort it took just to _speak_, and he wished he could stop, but his hips, his legs, his cock, didn't care about his fleeting wishes. They only wanted gratification, only wanted what the demon had said. Wanted to fuck, to take, to own.

"I'm sorry, I'm sorry, I'm so fucking-"

Castiel stole his words and his air at the same time, whining high-pitched and begging, a fresh wave of his slick leaking out over Dean's cock like an enticement he couldn't hope to resist.

"B-Breed... _Breed me_."

Dean was pretty much fucked after that point.

Whatever he'd managed to drag back of himself was overwhelmed by that, suffocated in the fury of _needwantmatebitchyes_ that seized him suddenly, Castiel's stammered pleas like liquid fire pouring over his body, igniting him inch by inch. He'd had his last bout of defiance, exhausted any fight left in him, and nothing could stop this now. They were lost.

Dean's hands grabbed Castiel by his slender hips and held him tight and still against Dean's groin, and then he was gone; slamming into Castiel's wet little hole—his fucking _cunt_, God—hips forcing cruelly into his bitch in complete abandon, fingers dragging Castiel back like he was little more than a toy to be used as rough hands pawed at him like they needed to prove to Castiel, to the _world_ just who owned him. Just who could make an Angel of the Lord moan and writhe like a slut on their cock, could make him beg and cry out for more.

He needed to see proof of it, to see marks and evidence littered all over Castiel's vessel, because it might have been these sons of bitches that were making them do this, but Castiel belonged to no one but himself, and Dean wasn't about to allow anyone to think otherwise.

Even later, he couldn't tell if that was what the demons had done to him, of if it was something worse. If it was just _Dean_.

Castiel was obscene under him, singing out mewled songs of desperate pleasure, all wild and unhinged and beautiful, like every filthy fantasy Dean had never allowed himself to have, and it was all _his_, belonged to _him_.

Castiel howled with Dean's increased vigour, neck stretched long and perfect, eyes closed in pleasured rapture and utter ruin as he got what he'd begged for. Quietly, Dean would later admit to himself how sorry he was that this was how he got to see Castiel like that for the first time.

It could have been different, been so much better, but the dreams he'd had of anything else were already melted, in shreds around them, hanging like entrails, and Dean might've wanted to weep for it another time. But not now.

"Yes, there's a good bitch, getting ready to take that knot, letting him knock your pussy up like a good girl."

The demon was still bleating on in the background, but it had stopped being important, stopped making any sense whatsoever, so Dean stopped listening, and when it happened, it punched him without warning in the stomach, sudden and hard, and the world around him snapped in two.

Dean's teeth were on Castiel's neck again, his cock driving deep into Castiel's depths, two, three more times before he was coming, impossible and earth shattering like a freight train had steamrollered into him and left him raw and obliterated afterwards, waves of his seed marking Castiel's insides white.

Barely-English growls and curses poured from his lips in an aggressive, babbling loop and he clung hard to Castiel, finding a kind of anchor in him as Dean's soul threatened to leave his body he was floating so high on this unstable mixture of familiar and alien sensation.

He shuddered and tensed like a tightly drawn violin string in excruciating pleasure, and then something was swelling, something new and terrifying. Dean screamed with it, his voice quickly joined by Castiel's shouts and then the angel was quivering, rippling around him as he came, his hot, rosy little pussy gushing with wetness around Dean's swollen—too swollen—cock, muscles milking him hungrily.

Dean gasped and snarled and cried with it, his body on meltdown with ecstasy and confusion as things that weren't supposed to shift shifted, things that weren't supposed to grow grew, and Castiel just kept squeezing, kept taking all of him like he was fucking _made_ for it.

Another wave of pleasure barraged into Dean like a stampede, and for all he could tell, he was coming impossibly all over again, adding to the thick mess already inside Castiel, sensations he should never have known assaulting every one of his senses.

And that was, finally, enough for him to black out.

...

When he woke again, Dean's face was buried against the sweat-damp skin of Castiel's neck, his body still thrumming amidst the sensory overload; nerves and flesh left polarised and tingling with electricity, endorphins flowing in riots without qualm in his bloodstream.

Dean groaned against Castiel's form, the stupor-fumes in his skull swirling and spinning still, but he could hear himself think now, at least, and that had to mean something good, right?

He heard Castiel's answering moan, and shame and guilt peaked out past the lingering clouds and glared right into his core and, fuck, _what had he done_? Dean tried to pull back, tried to get away, to... God, to just _do something_, but as he shifted, he felt a sore, unnatural tug at his groin, and Castiel let out a responding pained sound, his hands curling into white-knuckled fists in his cuffs.

"Don't-" Castiel croaked, his face turning in towards the leather, and Dean found himself instantly complying, staring with wide eyes down at where they were seemingly locked together, unnerved worry painted over shocked, tired features.

Castiel had his eyes closed, and Dean could hear his breathing was still ragged. He wondered how long he'd been out for. It couldn't have been all that long, but his wrists were bound once more, and when he looked around the cave again, he couldn't see the creatures for the darkness.

He almost snorted at the idea that they'd stepped out to give the two of them some privacy to talk. But God, what could he say? Where the fuck did he start?

Dean sighed, and it was a pathetic, miserable thing even to his own ears.

"Cas, I-"

Another wave of pleasure rolled through him and Dean's groan cut off his failing words, his body overflowing with blinding sensation as he involuntarily released another load of come into Castiel's ass. From the way Castiel tightened around him and let out a softened moan, it was pretty obvious that he was still right there with Dean as well.

Dean slumped against him again, his forehead resting on Castiel's shoulder as the aftershocks claimed him, the... whatever the fuck it was holding them together showing no signs of receding yet. They'd be here a while.

Dean found out later exactly what it was, exactly what the Lilu had done, how they'd taken him and Cas and moulded and marked up their bodies like fucking tools to meet their own fucked-up ends.

He'd already guessed the truth by the time Castiel had explained that Dean's cock was now in possession of a fully-functional, biological knot, but it was the angel's quiet and almost apologetic admission of his belief that he'd developed a goddamn _womb_ alongside these... heats of his that had Dean shutting off and slamming up steel walls once more.

What that meant, what that would mean for the two of them was something too grotesque, too gut-wrenching to consider, and nothing was as it seemed in purgatory, right? It wasn't real. It couldn't possibly be.

But it wasn't time to consider all of this yet. Dean couldn't see past his confusion to even ask these questions. He just concentrated on breathing, on trying not to move, on finding a way to come down.

"We're going to get out of here," Castiel said suddenly, solemn and surprisingly clear-sounding given all that had happened—was still happening—but what really grabbed Dean's attention was how sharp the words were, like furious razor blades Castiel wanted to hurl at their captors.

Hearing the surety in his voice, something in Dean somehow relaxed minutely, a slither of worry easing just a little, just with knowing that Castiel was just as angry, as hell-bent on getting out of here, and getting revenge, as Dean was.

And just like that, Dean felt it; the only emotion loud enough to beat out the disorientating cacophony within his body. Determination.

Between the two of them, they were some seriously stubborn sons of bitches too. Dean smiled, a sad, tiny thing, and nodded tiredly against Castiel's sweat-soaked hair.

"Yeah. Yeah we will."

He let out a breath and tested the give of his restraints once more, resolutely ignoring where he was still buried and tied-off balls deep in the body underneath him. He had something more important to focus on now, something to fight for, and it had planted hate and thirsty anger like seeds deep within him, fury already taking root. Castiel was right, they were gonna get out of this place.

And they were going to leave it bloody and barren behind them.

...

**A/N: **That's it for now, but I'm thinking about writing a sequel about the rest of the time they spend in captive, because it might be fun to explore more "breeding sessions", and to actually write knocked up!Cas because unf. And then maybe see them escape/get rescued? But I dunno yet. What do you guys think?


End file.
